Roentgen-ray tube.



J. E. LILIENFEILD.

I ROENTGEN RAY TUBE. APPLICATION FILED APR-17.1914RENEWED JULY 25.1916.

1,21 8,423.. Patented Mar; 6, 1917.

2 SHEETS-SHEET I.

woawto'z,

J E. LILIENFELD.

I ROENTGEN RAY TUBE. APPJLICATION mp0 APR. 11, 1914'. RENEWED JULY 25, I916.

Patented Mar. 6, 1917.

2 SHEETSSHEET 2.

JULIUS EDGAR LILIENFELD, or LEIPZIG, GERMANY.

ROENTGEN-RAY TUBE.

Specification of Letters Patent.

Application filed April 17, 1914, Serial No. 832,606. Renewed July 25, 1916. Serial No. 111,279.

To all whom it may concern:

Be it known that I, JULIUS EDGAR LILinN- FELD, subject of the AustroHungarian Emperor, residing at Leipzig, Germany, have invented certain new and useful Improvements in Roentgen-Ray Tubes; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in' the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

This invention relates to the production of- Roentgen rays and has special reference to'an apparatus designed to give high efficiency in the production of rays of this character. In order to obtain-a constant working of the tube in the production of such rays a high degree "of vacuum in the tube is essential. As pointed out in my companion application filed October 2, 1912, Serial No. 723,583, it is advisable to produce such a vacuum that no discharge will takeplace, under ordinary conditions, between the electrodes of the tube, the gas pressure being reduced to such a limit that conductivity in the spacev must be attained by means independent of the means for producing the discharge which effects the production. of the Roentgen rays before such discharge can take place.

As further pointed out in the above application, this conductivity is produced by means of an electrode heated to incandescence and which is preferably termed a glower electrode. In order to more efficiently and economically produce a tube of this description and to effect the production of Roentgen rays, it is necessary that the electrostatic field from the glower 'electrode or cathode to its anode shall not interfere. with the starting of the electrostatic field between the cathode and anticathode used for the production of rays.

This is of importance, as, for instance, when theproduction of extremely hard rays such as are used for therapeutic purposes is desired, because of the use of extremely high tensions, which. would disadvantageously affect the working of the glower discharge if the latter was not electrostatically screened from their influence. On the other hand,- if it be supposed that the glower discharge is absolutely electrostatmally at the highest tensions.

screened from the high-tension field between the cathode and anticathode there arises the advantage that the glower electrode may be positioned in any desired place without ref- Patented Mar. 6, 1917.

The principal objects of the present in- I vention are therefore to provide a tube. wherein there can be no interference botwecn. the electrostatic field from the glower cathode and its anode and the electrostatic field employed for production of rays even Second, that the field production between the cathode and anticathode shall not only not inhibit, but even assist in the production of a field between the cathode and anode used for the production of the rays.

With the above and other objects in view the invention consists in general ofcertain novel details of construction and combination of parts hereinafter fully described, illustrated in the accompanying drawings, and specifically claimed.

In the accompanying drawings, like characters of reference indicate like parts in the several views, and I Figure 1 is a section through one form of tube constructed inaccordance with this invention.

Fig. 2 is a section through a second formof tube constructed in accordance with this invention. I

In the form shown in Fig. 1, herein, there is employed a tube having the bulbs 10 and 11 which are connected by a neck 12, the part of the neck adj acent the bulb 10 being enlarged as at 13. Within the enlarged portion 13 the glass of the tube is extended to form a hollow cylindrical projection 14, the end of which supports the combined anode and cathode which consists of a suitable plate 15 curved to present a concave side of the bulb 10 and having adjacent its periphery a flange 16 which surrounds ,the

, end of the projection 14. Moreover the plate 15 is provided with perforations 17, one of which is preferably centrally located. Furthermore, within the bulb 10 is mounted the anti-cathode 18 preferably provided with a shield 19. In the bulb ll is a large loop of wire arranged as a glower cathode. This loop may extend as far from the main axis of the Roentgen electrodes as it is suitableto obtain the necessary glower surface for the purpose of working the tube with heavy currents (snap shots) 20 having suitable wiring connections 21 extending out of the bulb. Within the neck is located the anode 20 for the glower cathode 20. This anode may, if desired. be omitted so that the electrode 15 may act as a combined anode to the glower and cathode to the anticathodelS. i

In the form shown in Fig. 2 the'tube is provided with a pair'ot' bulbs 22 and 23. These bulbs are connected by a neck 21- and extending upward in this neck is a. hollow cylindrical projection 25 formed from the glass and spaced at its upper end from the walls of said neck. This glass projection is surrounded by a metallic cylinder 26 whereto is connected the combined cathode and anode 27 having a centrally disposed opening 28. Furthermore, within the cylindrical extension 25 is a second hollow cylindrical member 2!) which is held spaced from the first member by metallic screening members 30. The purpose of these electrostatically screening members is to prevent the discharge passing between the members 29 and 25 so that any discharge, in order to pass through the member 25, must also pass through the member 29; therefore the discharge is held within the inner member 29.

The upper end of the bulb 22 is provided withan inward tubular extension 31 which has fused in its inner end a metallic sleeve 32 carrying a second sleeve 33 which is closed at its inner end and supports the diagonally disposed anticathode 34. In the bulb 23 is provided a glower cathode 35 which may be heated through the usual wires 36. It will be notedthat this glower cathode .may have any desired position in reference to the axis of the tube without affecting the operation since it is electrostatically screened from the high tension field between the cathode and anticathode.

Each of these forms is provided withsuitable wiring connections as indicated in general at 37. s

It is to be noted that in each form thus described the discharge from the glower cathode will pass to the back of the combined cathode and anode and that by the impact ofthis discharge on the combined anode and cathode there is produced a condition suitable to start adischarge from the Roentgen cathode, the flow of the charged particles being in the same direction as the flow from the cathodic side of the combined anode and cathode.

Having thus described the invention, what is claimed as new, is i 1. In a Roentgen ray tube, the combination of a high vacuum tube, with a cathode and its anticathode, and a third electrode 2. In a Roentgen ray tube, the combination of a high vacuum tube, with a cathode and its anticathode, and a third electrode electrostatically screened from the anticathode and possessing the property of producing a discharge in a high vacuum, the first mentioned cathode being arranged between the anticathode and third electrode and serving as a screen between the third electrode and the anticathode.

In a Roentgen ray tube, the combination of a high vacuum tube, with a cathode and its anticathode, and a glower cathode electrostatically screened from the anticathode and possessing the property of producing a discharge in a high vacuum, the first mentioned cathode being arranged between the anticathode and the glower cathode.

4. A Roentgen ray tube provided with a cathode, an anticathode, and a third electrode between the cathode and anticathode consisting of a disk and having a perforation therein.

5. A Roentgen ray tube provided with a glower cathode, an anticathode, and a third electrode constituting a combined anode and cathode located between the first and second electrodes and having a perforation therein.

6. A Roentgen ray tube provided with a glower cathode, an anticathode, and a third electrode between the first two, said third electrode constituting the anode for the glower cathode and the cathode for the anticathode and being perforated as and for the purposes set forth. 5

7. A Roentgen ray tube provided with a glower cathode, an anti-cathode, and a third electrode between the first two, said third electrode constituting the anode for the glower cathode and the cathode for the anticathode and being perforated to receive impact of the discharge from the glower cathode, said tube being further arranged to concentrate the discharge of the glower on said perforated part of the third electrode.

8. A Roentgen ray tube including a pair of bulbs united by a neck and having a high vacuum, a septum across said neck and provided with a perforation, said septum constituting a combined cathode and anode, and an electrode in each bulb.

9. A Roentgen ray tube including a pair of bulbs united by a neck and having a high vacuum, a septum across said neck and provided with a perforation, said septum constituting a combined cathode and anode, an electrode in each bulb, and means within the neck to concentrate discharge to the perforation.

10. A Roentgen ray tube including a pair of bulbs united by a neck and having a high vacuum, a tubular projection extending from one end of said neck toward the other end thereof, a metallic sleeve on the free end of the tube, said sleeve carrying at its end a perforated diaphragm constituting an anode and cathode combined, a tube mounted withinthe rojection and spaced from the walls thereof metallic screens between the inner and outer tubes, a glower 'cathode which is located in the bulb at the base of the tubular projection, and an anticathode in the remaining bulb.

11. A Roentgen ray tube including a pair of bulbs united by a neck and having a high vacuum, a tubular projection extending from one end of said neck toward'the other end thereof, a metallic sleeve on the free end of the tube, said sleeve carrying at its end a perforated diaphragm constituting an anode and cathode combined, a tube mounted within the projection and spaced from the walls thereof and grounded to the said metallic sleeve, metallic screens between the inner and outer tubes, a glower cathode which is located in the bulb at base of the tubular projection, and an anticathode in the re- 

